I score 7 out of 20 in the short test and the description of being able to see through the bubble is about right. Frankly I'm surprised I scored so high. I have several friends and former colleagues who'd get close to zero.
The thing that helped my score is playing poker with a revolving group of couple hundred folks. I really get a chance to meet more typical Americans (although decent poker players are well above average intelligence otherwise they become broke). The limited discussions around the poker table involve sports, betting on sports, poker, sports history, movies, pop culture. Things like politics, or current events are almost never discussed and this despite that fact that any given time roughly 20% of the players have been to Iraq or Afghanistan. Investment and retirement planning never come up. In contrast to my non-poker friends where these subjects come up frequently.
Murray is right there is a huge cultural divide in America, I loved the Bell Curve, and will probably read this book too.